This invention relates to a coke oven and more particularly, a coke oven having an improved regenerator for reducing nitrogen oxides in waste gas generated in the coke oven thereby preventing environmental pollution.
In a known horizontal type coke oven, such as an Ottotype, Koppers-type and Carl-Still-type coke oven, fuel gas fed from one duct is heated and burned in a heating flue chamber for a predetermined time and the waste gas is discharged into atmosphere through a duct, a regenerator disposed below the heating flue chamber and a flue. The temperature of the waste gas entering into the regenerator is generally is about 750-1000.degree. C. In this process, bricks constituting the walls of the regenerator is heated by the high temperature waste gas and the heat is stored in the regenerator. The heat stored in the regenerator is fed to the heating flue chamber through another duct and is used for preheating air for the combustion.
The waste gas contains harmful substances, for example nitrogen oxides (abbreviated as NO.sub.x hereinbelow), which cause environmental air pollusion. In the prior art, such NO.sub.x were discharged through the flue of the coke oven into the atmosphere without being subjected to any treatment for removing NO.sub.x therefore, the discharged NO.sub.x became one factor that causes photochemical smog.